Need help with GTB racing hydraulic brakes.

[Chillin4life187]

Need help with GTB Racing hydraulic brakes. Whats the best way to fill and bleed the brakes? Anytime I fill the lines, I get air bubbles the second I let go of the syringe or attempt to loosen it from the connection. Thank you in advance.

 

[smurfer69]

OMG someone else with same problem,hi mate hows it going
u gotta keep pressure on syringe as u close each bleed screw
I don't know if u noticed but the instructions it shows an
exploded view of the calliper which shows clearly 1 piston
but the actual piston I have taken apart there is 2 side by side
if u connect just 1 calliper up and push like u would if installed
only 1 piston moves which means only 1 side of brake pad is getting
pressure , any thoughts your end

ps u can 2 or 3 at most 4 won't really affect braking
to be honest they are getting to be more trouble than
they are worth
and as you know they aint cheap, but look so nice

 

[Chillin4life187]

I guess my biggest issue was simply getting air in the line no matter what I did. So I got to thinking and realized the reason was. ..i wasnt taking the syringe and getting fluid all the way to the end. So there was always a small air bubble at the tip of the syringe which would get forced into the system as soon as I would squeeze the syringe. Now i take the syringe with the hose attached and slowly draw back until fluid is at the very tip of the RUBBER HOSE (the little rubber hose attached to the syringe with small ziptie.) I noticed its all in the fine details when it comes to the hydraulic system. Doing it this way you don't have to hold down on the syringe when you close the valve eithet bexause it doesn't have a vacuum effect. Make sense? Let me kniw if it works out for you. Maybe Ill post a video on youtube one of these days so others avoid the same issue.

 

[smurfer69]

umm sort of get what your doing , a vid would be good if u ever get round to it,
appreciate your response cheers pal

 

[smurfer69]

can I ask , the wheels are supposed to run freely
with the brakes off, with your brakes off how did you make
them run freely with brakes off, cos my wheels are so stiff rotors
do turn but its like they are 30/40% on before I even engage the brakes

 

[Chillin4life187]

Yes. The wheels are supposed to spin freely unless the brakes are applied. The rotors should be mounted and somewhat loose. The rotor tightens down once your wheels are put on and you tighten them. At that point, when you spin the wheel your wheel should spin FREELY with the rotor attached. If your brakes are grabbing it could be a number of things, but most common would be your brake/throttle linkage and the endpoints on your servo arm may need to be adjusted. Even just a simple 2mm adjustment can make a huge difference so be careful and adjust slowly.. Your servo may be slightly engaging the brakes even without you pressing the trigger on your transmitter. I would say 98% percent of the time its going to be those 2 reasons.
If your still having problems or have questions let me know and I can take some pics/video and send them to you.

 

[smurfer69]

your a diamond I will go through the procedure again more carefully cheers
for tips I didn't even think off appreciate it

 

[smurfer69]

well heres a few pics of my set up,i can see how the end points
make a big difference, but not enough to lock brakes up, im
maybe getting 20% brake, gonna try once more or so then its back to box

 

[integrated12345]

Hi Guys, i have just setup GTB Brakes on my 1/4 Sprintcar, no matter what way i try to bleed them as soon as i brake and hit the throttle air appears from the master cylinder hose connection, lots of small bubbles, i've tried bleeding from the caliper towards the master cylinder and vice versus, after a few minutes of track time the brakes just don't work from too much air, the system is new and everything is tightened correctly, no leaks too. I much prefer the real cars brake bleed nipple with the hose nipple so you can simply tighten the bleed nipple with the hose still connected instead of quickly trying to put a block off bolt back in while pushing the fluid threw slowly at the same time. Have any of you figured out a way to remove the air from the master cylinder?